Sometimes definite articles in other languages are used grammatically, but not necessarily meaningfully. By that I mean, if you say, The girls drink water, it is still definite. The girls drink the water is also definite. shrug it's complicated.
Then again, perhaps this translation is wrong.
there is a good post explaining it here: https://forum.duolingo.com/comment/1012366/When-to-use-the-definite-article
Type in any Italian verb here: https://www.italian-verbs.com/italian-verbs/conjugation.php?parola=entrare
"Le", in this context, is a plural form, yes, but not for "she". "Le" in this context is the same as the English "the". It has the same meaning as the singular "la", as well as others like "lo", "il", "i", and "l'". Definite articles and how they affect other words in Italian can take some getting used to.
"Lei" (which is pronounced similarly to le) is the word for "she".
Is that the question you were asking?
I know that when you have two vowels next to each other, as in 'o' in bevono and the 'a' in acqua that the apostrophe 'l' is used for smoother pronunciation. It's like the words 'a' and 'an' in English. In English we wouldn't say, 'The girls ate a apple.' We say, 'The girls ate an apple.' Hope that's helpful.